Some specimens of fluorite (CaF{2}) show the phenomenon especially well, whence the name fluorescence.
If kept in the dark for a long time no trace of light appears when fluorite is placed at a temperature of 100 deg.
Fluorite is widely distributed, most commonly in vein deposits, often associated with metallic ores.
Some fissure veins of fluorite in limestone in southern Illinois are twenty to forty feet wide.
The fluorite and associated minerals were probably deposited by hot solutions bringing the material from some large underlying igneous mass of which the dikes are off-shoots.
In England, fluorite is obtained in this manner as a by-product from lead and zinc mines.
The large fluorspar deposits of Illinois and Kentucky contain fluorite with calcite, barite, and metallic sulphides, in wide veins filling fissures in limestones and sandstones and replacing the fissure walls.
They found that quartz and fluorite possessed the property of selective reflection for rays of wave-length 8.
The intensities were corrected and reduced to a wave-length scale with the aid of Paschen's results on the dispersion formula of fluorite (Wied.
Paschen, and Lummer and Pringsheim verified this relation by observing with a bolometer the intensity at different points in the spectrum produced by a fluorite prism.
The residual impurity at any stage could be estimated by interposing a thin plate of quartz or fluorite which completely reflected or absorbed the residual rays, but allowed the impurity to pass.
Beckmann, under the direction of Rubens, investigated the variation with temperature of the residual rays reflected from fluorite employing sources from -80 deg.
The central band (f g) is a darker fluorite containing irregular masses of galenite.
In this the gangue minerals are fluorite (f) and barite (b).
Talc and gypsum are easily scratched with the nail; calcite and fluorite yield easily to the knife or file, apatite with more difficulty; while orthoclase is near the limit of the hardness of ordinary steel, and quartz is entirely beyond it.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "fluorite" in a variety of sentences. We hope that you will now be able to make sentences using this word.
